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ARTICLE XV.—THE SMALL BOTTOM AND SHORE FAUNA OF THE 
MIDDLE AND LOWER ILLINOIS RIVER AND ITS CONNECTING 
LAKES, CHILLICOTHE TO GRAFTON: ITS VALUATION; ITS 
SOURCES OF FOOD SUPPLY; AND ITS RELATION TO THE 
FISHERY. BY ROBERT E. RICHARDSON. (6 TrExt-FIGURES, 1 
PROFILE, 8 Mars WITH INDEX SHEET): JUNE, 1921.................45. 
SEIS UT RRS oe BEAR SS S18. C6 CRO GCC ERI CE IIR ISeTE RC En IR Ee R ore RACE ene 
Bere SRREST ch ns PRTER IEE SA DD i etek ara stor cto evagevel sist aastisk clay oiiciaysusiiaycisie:"eres Gsels'sve t/a asa e\aietay eee: 
Hydrography and bottom fauna, Illinois River, Chillicothe to Grafton, 
APL VC UO De Melo talatntereMetanerercistaiclctarelcteretessie! cies) < aetdie-e oisie muaisceiete of 
(a) Chillicothe to foot of Peoria Lake (18.5 miles)................ 
(bv) Foot of Peoria Lake to Pekin (9 miles).........-.-......000- 
(c) Pekin to Copperas Creek dam (16.2 TIRLIGS)) aperetervreiate siete oe) ensvereteace 
(ad) Copperas Creek dam to Havana (16.8 miles).................. 
fer Havana to Laprance dan (42:5 miles) ooo. ccc cc cca cene 
(7) Lagrange dam\'to Grafton? (77:5 miles) 20... 12. ccc eens 
(g) General summary, Illinois River bottom fauna, July—October, 
HOititeanae eee Aas eS oteb cig BOC RICE SOE ECO ae een 
The bottom fauna of the lakes and ponds of the Illinois River bottom- 
lands between Copperas Creek dam and Lagrange, July—October, 
Tg We WG ois gota Sincigad COC LO OOC.ODICE.c Olt POUCH DO OEE OO Ie cE Eni. 
The weed fauna of the 1-4 foot zone of the Illinois valley lakes, and 
the combined bottom- and weed-fauna average, August—October, 1914- 
The bottom- and weed-fauna of the littoral zone of the deep glacial 
lakes of northeastern Illinois, August—October, 1916................ 
Comparison with outside bottom- and weed-fauna valuations........ 
The food of certain small bottom-invertebrates in the river channel 
at Havana and the general composition of the detritus............ 
The nitrogen, organic carbon, and other oxidizable matter in the 
bottom muds of the river and lakes below Chillicothe, 1913-1914.... 
The plankton and other limnetic oxidizable matters carried by the 
Illinois River channel at Chillicothe and Havana, 1909-1914........ 
General comparison of the Illinois River and its connecting lakes in 
the food resources of a fishery and in fish output.................. 
The reproductive rate of the bottom animals................2+.00005 
Changes in the quantity of the bottom-fauna stocks between 1913 
ERED LOT Diimeratere teksto ero tel eta rieiet ekerotns aie eis ic icra dielvie.cie%s) els. alplv)eileic/sue-c)S:\e/ain1s «che 
Detailed valuation tables:— 
I. Bottom fauna, Illinois River, 1915..............ccee eee ee eees 
II. Bottom fauna of the lakes of the Illinois valley, Copperas Creek 
dam’ to Mapransey 1914191 5 cis ice cc cisculec cas cel es es eess c's 
III. Weed fauna 1- to 4-foot zone, lakes and backwaters in vicinity 
Re Eek Vict 1) ome Aeon terete ators nrstale avec racs (oleh euele¢) shavalelesveieicle(e)scare/sinin clei 
IV. Bottom and weed fauna, littoral zone of glacial lakes of north- 
EASHSrTHMMUININO IS OL ITG cae. ons, 8 oes atsieiaitlele d's Srsvareielves > 
ESS TTT PME ITN Vane eer Stes esol e ote ato) ajar ctsiataleie,wifaveiieseieini aesincreteiausterereie eve eualeters 
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